Papers by Author: Ying Jun Wang

Abstract: In order to form the firm active fixation with the adjacent bone, a new kind of bioactive composite hydrogel was prepared as calcic layer of cartilage with polyvinyl alcohol (PVA) and bioglass (BG). The biomineralization properties of the PVA/BG biocomposite hydrogel were studied through Fourier transformed infrared spectroscopy, XRD and SEM with EDX. Results showed that hydroxylcarbonateapatite was formed on the surface of the PVA/BG biocomposite hydrogel after the biocomposite hydrogel soaked into SBF solution. The composite possesses good mineralization properties and could form good firm active fixation with the adjacent bone.

Abstract: Porous HA/TCP bioceramics were immersed in pure bovine serum to observe the growth and formation of apatite. HRTEM, FTIR, and SEM coupled with EDS were used for the characterization of immersed samples. SEM results showed that some beamed crystals formed on the surface of ceramics granules, and with postponement of immersion time, crystals extended and became bigger, strap-like crystals became sheet-like crystals. HRTEM observations indicated that new-formed crystals developed along axes direction according to parallel layers. IR spectrum showed CO3 2- characteristic peaks existed besides O-P-O and OH- characteristic peaks. EDS results showed that calcium and phosphor ratio was 1.95 (mol ratio). The results indicated that bovine serums were advantaged to bone-like apatite formation.

Abstract: The bioactive synthetic hydrogel materials were prepared with polyethylene glycol diacrylate (PEGDA) and 2-hydroxyethyl mathacrylate (HEMA) by UV photo-polymerization. The aim of this study was to prepare a scaffold material by combining HEMA into a composite polymeric PEGDA-based hydrogel, which were used as bioactive artificial cartilage. The structure and properties of the synthetic hydrogels were investigated in details using FTIR techniques. The swelling data indicated that the equilibrium water content depended on the precursor feed ratio. It was found that adding the HEMA into the PEGDA-based hydrogels was very helpful to improve the swelling properties.

Abstract: In the present study, bioactive functional gradient coatings were prepared using net-energy controlled plasma spraying technology. The microstructure and phases of the bioactive functional gradient coating were examined by means of transmission electron microscope, scanning electron microscopy and X-ray diffraction. The results revealed that: (1) as-sprayed coatings contained a large amount of amorphous phases and some nano-sized HA crystals formed during rapid solidification, (2) surface of the coating was very rough with different-sized micropores, and the gradient layer was much denser which firmly bonded to the substrate without gaps and obvious interface between the coating and the substrate

Abstract: An injectable calcium phosphate bone cement was prepared by combining amorphous calcium phosphate (ACP) and dicalcium phosphate dihydrate (DCPD) for use in non-invasive surgery in this work. The effect of the conserving time on the viscosity, yield stress and injectability of the calcium phosphate cement (CPC) pastes were studied. The results showed that as the conserving time of the pastes prolonged, the viscosity and the yield stress of the pastes increased exponentially, and the injectability of the pastes decreased. This resulted from the transformation of DCPD and ACP into hydroxyapatite via hydration reaction. The results also indicated that the pastes still exhibited good injectability in even 15 min after preparation of the CPC pastes.

Abstract: The bone tissue engineering scaffold was developed by compounded the type I collagen with the porous scaffold of the sol-gel derived bioactive glass (BG) in the system CaO-P2O5-SiO2. The resultant porous scaffold was treated in supersaturated calcification solution (SCS) to form the surface layer of hydroxyl-carbonate-apatite (HCA) since the type I collagen possessed good biocompatibility and bio-absorbability, and also, the ability of inducting calcium phosphates to precipitated inside and outside the collagen fibers where the collagen fibers acted as bio-macromolecules template for formation of bone-like inorganic minerals in nature bone such as: octo-calcium phosphate (OCP), tri-calcium phosphate (TCP) and hydroxyl-carbonate-apatite (HCA). On the other hand, the sol-gel derived bioactive glass also played an important role in formation of the above bio-minerals owing to its serial chemical reactions with the body fluid. The in vitro study in supersaturated calcification solution SCS indicated that the surface of the porous scaffold was able to induce formation of bone-like HCA crystals on the pore walls of the scaffold which possessed satisfactory cells biocompatibility.

Abstract: In this article, a multilayer tissue engineering scaffold has been fabricated. The uppermost layer is consisted by the collagen and the downmost layer is consisted by the collagen/hydroxyapatide. Between the two layers, there have several continues changed collagen/HA layers at different ratio. These gradient scaffolds have been made by the freeze dried method. The morphology of the multiphase scaffold has been observed by the SEM. The chondrocytes from New Zealand rabbit knee joint were separated, harvested and cultured on the top layer of the scaffold. The histological and the immunohistochemical testing show that the chondrocytes keep its normal type in the 2 culture weeks.

Abstract: Dense HA/TCP bioceramics were immersed in pure bovine serum, rabbit serum and dog serum to observe apatite formation. Deposited crystals were examined using SEM. Results showed that some needle-like crystals formed on surface of sterilized HA/TCP, and needle crystals developed into sheet crystals and stick crystals after ceramics were immersed in bovine serum and rabbit serum respectively. The growth of crystals was maybe affected by the content of calcium, various kinds of albumen and alkaline phosphatase in different serums and the different pH of serum.

Abstract: The spherical nano-sized bioactive particles in the system of CaO-P2O5-SiO2 were bio-mimetically synthesized using micro-emulsion method. The microstructures and properties of the bio- mimetic nano-materials were characterized using XRD, FTIR, SEM/EDAX and TEM techniques. It was indicated that the nano-particles possessed glassy structural characteristics. The porous composite for bone tissue reconstruction was prepared by compounding poly (hydroxybutyrate-2-co-2-hydroxyvalerate) (PHBV) and the nano-particles of bio-mimetic bioactive glasses (BMBG). Bone-like hydroxyl- carbonate-apatite (HCA) could formed on the surface of porous composite by immersing the composite in simulated body fluid (SBF) at 37°C for 8 hours. With increase of immersion time, the morphology of HCA changed from spherical into flake-like crystals. The study on cells attachment of the porous PHBV/BMBG composite proved that the material possessed satisfactory bioactivity, bio-mineralization function and cells biocompatibility.

Abstract: A porous bioglass reinforced tricalcium phosphate scaffold was prepared. The microstructure, degradability and reaction products of the scaffold after immersed in a simulated body fluid for different days were emphatically investigated using scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, Fourier transformed infrared spectroscopy and induced coupled plasma spectroscopy. The results showed that a homogeneous hydroxy-carbonate-apatite (HCA) layer forms on the surface of the scaffold for over 30- day immersion and the oriented growth of the HCA occurs. In addition, this paper discussed the competing mechanism between the dissolution and the precipitation via the measurement of calcium and silicon ionic concentrations in the SBF.